Refrigerating apparatus of the absorption type



May 15, 1923. 1,455,701

E. ALTENKIRCH REFRIGERATING APPARATUS OF THE ABSORPTION TYPE Filed Aug. 14 1922 2 Sheets-Sheet 1 May 15, 1923. 1A55JM E. ALTENKIRCH REFRIGERATING APPARATUS OF THE ABSORPTION TYPE Filed Aug. 14, 1922 2 Sheet s -Sheet 2 Patented ay 15, 1923.

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EDMUND ALTENKIRCH, OF FREDEBSDOR-F, NEAR ALT-LANDSBERG, GERMANY,

ASSIGNOR TO SIEMENS-SCHUCKERTWERKE GESELLSCHAFT MIT BESCHRANK- TER HAFTUNG, OF SIEMENSSTADT, NEAR BERLIN, GERMANY, A GERMAN COR- PORATION.

REFRIGERATING APPARATUS THE ABSORPTION TYPE.

Application filed August 14, 1922. Serial No. 581,775.

To all whom it may concern Be it known that I, EDMUND ALTnNKInoH, .a citizen of the German Empire, residing at F redersdorf. near Alt-Landsberg, Ostbahn, Germany, have invented certain new and useful Improvements in or Relating to Refrigerating Apparatus of the Absorption Type, of which the following is a specifi' cation.

This invention relates to refrigerating apparatus of the absorption type. In known apparatus of this type the gz1s-enrlched liquid is caused to pass from the part of the apparatus termed the absorber by means of a pump into a high pressure chamber in which it is deprived of gas by heat, this chamber being herein termed the boiler. This pump is the most delicate part of the apparatus, and the chief object of the present invention is to render it unnecessary.

According to the invention the absorber is arranged at such a height above the inlet of the boiler that the column of liquid in a conduit interposed between the absorber and the boiler maintains the necessary difference of pressure between the said absorber and the said boiler;

In order that the said invention may be clearly understood and readily carried into effect the same will now be described more fully with reference to the accompanying drawings, in which Figure 1 is a section showing one constructional form of apparatus in accordance with the invention,

Figure 2 is a similar View showing. a second constructional form, and

Figure 3 is also a similar View showing a third constructional form.

In Figure 1, the absorber is indicated by 1 and the boiler is indicated by 2.- The absorber and boiler are connected together by a pipe 3. A second pipe 114 which leads upwards to the absorber 1, dips at its lower end into the liquid contained in the boiler 2. The absorber 1 is surrounded by a cooling jacket 4 having an inlet 5 and an outlet 6 for the cooling medium. The boiler 2 is placed in a chamber 7 having an inlet opening 8 and an outlet opening 9 for the heating medium. Next to the boiler 2 is arranged the condenser 13 and between them is placed. a partition 101 of such a height as to revent any liquid from passing from one chamber into the other, whilst the gas spaces are in communication with each other. The condenser 13 is surrounded by a cooling device 15 having an inlet 16 and an outlet 17 for the cooling medium. Next to the absorber 1 is arranged the evaporator 19 with a partition 102 between the two to avoid any exchange of liquid, .without however preventing thegases or vapours from passing over. A pipe 18 which opens into the evaporator 19, dips into the liquid contained in the condenser 13. The evaporator 19 is surrounded by a jacket 20 through which passes the medium to be cooled. The said medium is admitted at 21 and escapes at 22. The liquid used in the working of the apparatus can be any desired binary mixture which should be selected to suit the pressures employed in the ap aratus and the temperatures to be ultimate y obtained. For instance, sulphuric acid and water could be used, in which case the absorber'l as well as the boiler 2 will contain a mixture of sulphuric acid and water, and the condenser ].3 and the evaporator 19 pure water.

The working of the apparatus is as follows :-Owing to the heating to which the water and sulphuric acid mixture is-subjected in the boiler 2 steam isexpelled and passes into the condenser 13 in which the steam is condensedby cooling. A few bubbles of steam are also produced in the lower part of the pipe 114, and rise in the said pipe. This results in an upward movement of the liquid in the pipe 114, although at first the said movement will be a slow one. When the heated liquid reaches the upper part of the said pipe, its pressure will decrease. and owing to the said decrease of pressure more steam bubbles will be formed which will also rise in the pipe 114 and conin the condenser 13 by the condensation of the steam rises in the pipe 18, partly owing .to. the existence of a higher pressure in the condenser 13. Owing to the relief from pressure in the upper part of the pipe 18 steam bubbles will be formed which will contribute to the rising of the liquid. The water is then vaporized in the evaporator 19, and efi'ects cooling of the medium flowing through the jacket 20. As will be seen from the drawing no pump is required nor are any throttling or regulating valves necessary.

In the construction according to Figure 1, a number of steam bubbles pass through the pipe 114 direct into the absorber 1, and are absorbed again without having in any way contributed to the production of cold.

It is possible to avoid this by a suitable arrangement of the heating jacket 7 and by cooling of the pipe 114. In the construction illustrated by Figure 1, the steam bubbles rising in the pipe 114 must not however be suppressed as they maintain circulation. of liquid'between the boiler 2 and the absorber 1 as aforesaid.

The apparatus according to the invention has been further developed in such a manner that the whole quantity of steam generated in the boiler 2 can be utilized for assisting in the liquid circulation, without its being necessary however to convey any quantities of steam from the boiler direct into the absorber. For this purpose a separate gas separation chamber is provided from which a pipe for the gas leads to the condenser and a pipe for the liquid leads to the absorber, whilst the mixture of liquid and. separated gas is supplied to the said separation chamber through a pipe leading from the boiler. The gas separation chamber can be arranged at any desired level. Consequently it is pos sible to arrange it at such a level, that the steam pressure alone is sufficient for forcing the liquid (deprived of gas from the gas separation chamber upwards into the absorber, even when there are considerable liquid resistances to be overcome. In the pipe which leads from the boiler into the gas separation chamber, the rising gas bubbles produce the upward movement of the liquid. An example of a construction of this nature is shown in Figure 2. The absorber 1, the boiler 2, the condenser 13 and the evaporator 19 with their cooling and heating'devices are substantially the same as in Figure 1. The boiler 2 and the condneser 13 are however completely shut ofl from each other by a partition 111. Above the boiler 2 is situated the gas separation chamber 10. From the latter a pipe 12 for the gas leads into the condenser 13. A pipe 14 which dips into the liquid contained in the chamber 10, leads to the absorber 1. The cooling jacket 104 of the absorber has an extension 44 so that the pipe 14 into the absorber 1. The gas separationchamber 10 is arranged at a sufliciently high level, so that the difference of pressure in the chamber 10 and the absorber 1 amply overcomes the pressure of the liquid column and the friction in the pipe 14, although no further gas bubbles are produced in the said pipe, owing to the cooling of this pipe as aforesaid. As the pressure determined by the temperature in the condenser 13 obtains also in the gas separation chamber 10, the pressure in the boiler 2 is greater in view of its lower position with respect to the gas separation chamber than the pressure in the condenser 13. In order to ensure that the liquid column in the pipe 3 shall balance this greater pressure, it must be c0r respondingly longer, that is to say the height between the absorber 1 and the boiler 2 must be greater than in the apparatus shown in Figure 1.'

The upward drive of the liquid in the pipe 11, which is caused by the rising bubbles of the whole steam expelled, is so considerable that the gas separation chamber '10 could be arranged above the absorber 1. Under certain conditions such a construction has special. advantages Which will be explained .interior of which it is bent downwards. To

the. vessel 41 is connected the boiler which is constituted by a helically wound glass tube 32 surrounding a heating cylinder 33. The heating cylinder is made of asbestos in the interior of which are mounted electric resistance wires to which current is supplied through the wires 34 and 35. The glass tube 32 opens into the gas separation chamber 36 which, as shown in the drawing, is arranged at a higher level than the absorber 30. The gas separation chamber 36 is connected by a pipe 37 to the condenser 38 and further by a pipe 39 and a capillary tube 40, to the absorber 30. In the absorber 30 is, arranged a cooling coil 49, and in the condenser 38 a cooling coil 50 these coils being connected together by a pipe 51. Cooling water is admitted at 52 and escapes at 53.

From the condenser 38 a capillary tube 56 leads into the evaporator 54 arranged below the condenser and in the interior of the evaporator is arranged a pipe 55 through which passes the medium to be coooled. A pipe 57 leads from the evaporator 54 into the absorber 36; moreover one of the lowest points of the evaporator 54 is connected to the absorber 30 by means of a capillary tube 43.

The spherical vessel 41 is connected by a pipe 47 to a gas cushion chamber 48 and the latter is connected to the pipe 37 by a short length of piping 42. The pipe 31 is provided with a supporting foot 58 and the heating cylinder 33 with a supporting foot 59.

The working of the apparatus shown in Figure 3 is as follows :The gas-enriched solution flows from the absorber 30 through the pipe 31 into the spherical vessel 41 and from the latter into the boiler 32. In the latter the solution is heated by means of the electrically heated cylinder 33 so that water vapour or steam is generated. As soon as v a steam bubble is separated, it rises in the pipe 32 following the windings of the said pipe, and in the said rising movement the liquid contained in the boiler participates. In this construction the boiler 32 is as described itself formed into a rising pipe, unlike the construction in Figure 2 where the two parts,-namely the boiler 2 and the pipe 11, are two distinctly separate elements. The construction according to Figure 3 has the advantage that each steam bubble sepaated contributes to the upward movement of the liquid immediately on its generation. Moreover, the helical shape att'ords an ample heating surface and imparts to the pipe considerable elasticity, which is of great importance as when the mixtureof'sulphuric acid and water is heated gas expulsion frequently takes place suddenly and with violent shocks. The length of the pipe 32 and its elasticity also contribute to keeping the liquid therein in constant movement. This reduces the retardation or delay in boiling, and no excessively violent shocks take place. In spite of this it may happen, when starting the apparatus and when there is as yet no movement of the liquid, that the first boiling shock which is frequently very violent will not only drive the liquid into the chamber 36, but also force it back into the absorber 30. Generally, such a transitory phenomenon does not cause much trouble, more particularly when it happens only at the beginning of the working. In order to avoid it however the vessel. 41 is' as aforesaid placed between the pipe 31 and the boiler 32. Any gas that may be forced back from the boiler 32, cannot enter the pipe 31 as the latter is bent downwards as shown in the figure. On the contrary, the gas will rise in the pipe 47 and pass into the cushion chamber 48 and thence through the pipe 42 and the pipe 37 into the condenser. In the case of quiet working the vessel 41 and the lower part of the pipe 47 are filled with liquid up to the height H. The level of the liquid at H gives the true liquid level in the boiler 32 which, in this constructional form also lies below the liquid level in the absorber 30.

The gas-deprived sulphuric acid passes from the gas separation chamber 36 through the pipe 39 and the capillary tube 40 into the absorber 30. The object of the insertion of the capillary tube is as follows :-During working the premure in the gas separation chamber 36 is the same as in the condenser 38. In order to keep the said pressure always greater than the lower pressure in the absorber 30, a liquid resistance must be placed in the connecting pipe between the gas separation chamber and the absorber. This resistance is constituted by the capillary'tube 40. The movement of the liquid through the said capillary tube is however due not only to the higher pressure of gas in the chamber 36, but also to the higher level which the liquid will generally assume in the gas separation chamber 36 or in the pipe 39, provided of course that the apparatus is filled with sufiicient liquid. Owing to this double pressure action, uniformity of circulation is ensured. If for instance. the pressure in the condenser 38 and therefore in the gas separation chamber 36 should temporarily fall for any reason, the static pressure due to the head of liquid in the pipe 39 could nevertheless maintain the supply of liquid to the absorber 30.

As shown in Figure 3, the pipe 39 with the capillary tube 40 form a U-pipe the object'v of whichis to prevent the water vapour or steam from paming direct from the gas separation chamber 36 into the absorber '30 if for any reason there is not a suflicient supply of gas-deprived acid. If the chamber 36 becomes completely empty of liquid, and the level of liquid in the pipe 39 also sinks sufficiently low the excess of pressure of the liquid column which will then still remain in the capillary tube 40, will balance the gas premure in the gas separation chamber 36. Consequently the liquid will remain stationary and the steam will be unable to pass into the absorber 30.

The expelled water vapour or steam passes from the gas separation chamber into the condenser 38 where it is condensed, The cooling water flowing through the cooling coil 50 and escaping at 53, will carry away the heat of condensation.

The water flows from the condenser 38 4 tion of the Water.

cial advantage. In the arrangement shown" in Figure 2, a certain stock of liquid is assumed to exist both in the condenser 13 and in the evaporator 19, which is of value for uniformity of working. In many cases however, the stock of liquid'in the evaporator is of little use. It is necessary to bear in mind that small quantities of sulphuric acid amended by the Water vapour or steam from the gas se aration chamber 10 into the condenser 13. wing to the evaporation of the water in the evaporator 19, these small quantities of sulphuric acid come to the surface and gradually prevent further evapora- The stock'of water is therefore of greater value when in the condenser than in the evaporator. To be able to utilize it under any conditions, it is necessary to make sure of conveying it into the evaporator even if the pressure in the condenser should temporarily fall. In the construction shown in Figure 2, if there is insufiicient pressure the stock of water would remain in the condenser 13 and evaporation and therefore generation of cold would be interrupted. If however. the condenser 38 is arranged above the evaporator 54 as in Figure 3, the water stored in the condenser 38 would in any case gradually run by gravity into the evaporat0r=54 and thus maintain the working of the apparatus for-a time even when the necessary difference of pressure between the two is temporarily non-existent. The small quantities of sulphuric acid that may pass into the condenser 38, are also carried by the water through the capillary tube 56 and thus pass into the evaporator 54. Hence they can return into the absorber 30 through the capillary tube 43. The water vapour or steam returns from the evaporator 54 through the pipe 57 to the absorber 30 where it is absorbed by the gas-deprived sulphuric acid and the cycle begins again. The heat generated is carried away by the cooling coil 49.

The apparatus is not limited to its use for refrigerating alone as the heat generated can also be utilized in any desired manner as is'known in existing refrigerating apparatus. After the cooling water has passed through the pipe coils 49 and 50 it may not be allowed simply to run off but its heat may be utilized in any suitable manner. Any other liquid or gaseous medium can also be used for being heated and subsequently employed (for example) for heating, saturating, chemical or other purposes by passing it through the pipe coils 49 and 50. The heat which is thus obtained for useful purposes, is greater than that required for heating the pipe 32. The apparatus shown in Figure 2 thus becomes an electric heating apparatus in which the energy represented by heat units delivered is greater than the energy represented by the quantity of elec-- tric current consumed, on account of those heat units being included which are derived from the medium to be cooled.

What I claim and desire to secure by Letters Patent of the United States is In refrigerating apparatus of the absorption type the combination of a boiler for containing an absorption liquid and heating means for disengaging a vapor from the absorption liquid, an absorber for containing an absorption liquid and' a vapor to be absorbed, an uninterrupted conduit interposed between the absorber and the boiler and adapted to convey the absorption liquid from the absorber to the boiler and means In testimoig whereof I aflix my si nature. DMUND' ALTENKI tCH. 

